Shikimic acid is a common biosynthetic intermediate of various aromatic compounds in plants and microorganisms, and is a very important substance to plants and microorganisms. Further, shikimic acid is a very useful compound used as a raw material for manufacturing Oseltamivir (TAMIFLU) (registered trademark), a medicine to treat new strains of influenza, as well as a lot of medicines and agricultural chemicals.
Currently, shikimic acid is mainly produced by extracting and purifying from Illicium verum (star anise). However, due to a problem that the content of component is not constant in the case of extracting from natural products, methods for stably producing shikimic acid still have been pursued. For example, as synthetic production approaches, a method for preparing shikimic acid derivatives by selective dehydration from quinic acid using Vilsmeier reagent (Patent Publication 1), a method for producing diaminoshikimic acid from isophthalic acid(Patent Publication 2), and a method for preparing diaminoshikimic acid from furan (Patent Publication 3), etc. have been reported. All of these methods are the methods for producing shikimic acid derivatives and further step(s) is (are) required to obtain target shikimic acid.
In addition, as other production methods from quinic acid, a method for producing shikimic acid in two steps by using shikimic acid dehydrogenase and glucose dehydrogenase derived from an acetobactor (Patent Publication 4) and a method converting quinic acid to an acetal of quinic acid ester followed by producing shikimic acid from the acetal (Patent Publication 5), etc. have been reported. As production methods using microorganisms, the methods utilizing a Citrobacter microorganism (Patent Publication 6 and 7), etc. have been reported; further, a method for producing shikimic acid by using chlorogenic acid contained in coffee grounds as a raw material together with a microorganism that has chlorogenic acid hydrolase as a microbial catalyst (Patent Publication 8), etc. has been reported. Moreover, as a production method of shikimic acid by fermentation using E. coli has been reported (Non-patent Publication 1).
On the other hand, the inventors of the present invention so far have reported that the mycelial growth of Pleurotus ostreatus, a type of basidiomycetes, is suppressed by blue light, and also that gene expression response to blue light is observed (Non-patent Publication 2 and 3). However, it is totally unknown what kinds of metabolites are produced, when Pleurotus ostreatus is stimulated by blue light and the growth thereof is suppressed.